Connective tissue
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Most abundant and widely distributed tissues in the body
Binds, support, and strengthen body tissues, protect and insulate
internal organ, serve as major transport system, compartmentalizes
structures such as skeletal muscles, storage, Immune responses
It consists of 2 basic element: extracellular matrix and cells
Highly vascular
Supplied by nerves
Mesenchymal cells give rise to cells of connective tissue
Types of connective tissue cells
Fibroblast
 Adipocytes
 Mast cells
 WBC
 Macrophages
 Plasma cells
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Connective tissue cells
1) Fibroblasts:
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Large, flat cells with branching
processes most numerous.
Present in all the general
connective tissues
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Secrete the fibers and certain
components of the ground
substance of the extracellular
matrix.
2) Adipocytes:
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Store triglycerides (fats).
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Deep to the skin and around
organs such as the heart and
kidneys.
Connective tissue cells
3) Plasma cells:
 Develop from a type of white blood
cell called a B lymphocyte.
 Secrete antibodies
 Found in the gastrointestinal and
respiratory tracts, salivary glands,
lymph nodes, spleen, and red bone
marrow.
4) Mast cells:
 Abundant alongside the blood
vessels that supply connective
tissue.
 Produce histamine, a chemical that
dilates small blood vessels as part
of the inflammatory response, the
body’s reaction to injury or
infection.
 Produces heparin
Connective tissue cells
5) White blood cells:
6) Macrophages:
 Develop from monocytes, a type of
white blood cell.
 Irregular shape with short
branching projections
 Capable of engulfing bacteria and
cellular debris
 Types:
1) Fixed macrophages: reside in a
particular tissue; i.e. alveolar
macrophages in the lungs or
splenic macrophages in the spleen.
2) Wandering macrophages: have the
ability to move throughout the
tissue and gather at sites of
infection or inflammation to carry
out phagocytosis.
Extracellular matrix (ECM)
Ground substances
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May be fluid, semifluid, gelatinous or calcified
It supports cells, bind them together, store water, provide
medium for exchange, it also play role in how tissue migrate,
proliferate and change shape, and in how they carry out their
metabolic functions
It contains water, and large organic molecules such as
polysaccharides and proteins, and adhesion proteins
(Hyaluronic acid, Chondroitin sulfate, dermatan sulfate,
keratan sulfate and fibronectin)
Fibers
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Collagen fibers
Elastic fibers
Reticular fibers
Collagen fibers
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Very strong and resist pulling forces (tension), but they are not stiff,
which allows tissue flexibility.
Vary from tissue to another. Collagen fibers in cartilage are
surrounded by more water molecules than those in bone, which
gives cartilage a more cushioning effect.
Can occur in parallel bundles (dense regular connective tissue).
great tensile strength.
Consist of the protein collagen, most abundant protein in the body,
25 percent of total.
Elastic fibers
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Smaller in diameter than collagen fibers
branch and join together to form a network within a tissue.
Consists of molecules of the protein elastin surrounded by a
glycoprotein named fibrillin, which adds strength and stability.
Strong but can be stretched up to 150% of their relaxed length
without breaking.
Have the ability to return to their original shape after being
stretched, (elasticity).
Found in skin, blood vessel walls, and lung tissue.
Reticular fibers
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Consist of collagen arranged in fine bundles with a coating of
glycoprotein,
provide support in the walls of blood vessels and form a
network around the cells in some tissues, such as areolar
connective tissue, adipose tissue, nerve fibers, and smooth
muscle tissue.
Produced by fibroblasts.
Much thinner than collagen fibers and form branching
networks to provide support and strength.
Found in reticular connective tissue, stroma or supporting
framework of many soft organs, such as the spleen and lymph
nodes. also help to form the basement membrane.
Classification of connective tissue
I.
Embryonic connective tissue
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b.
II.
Mesenchyme
Mucous connective tissue
Mature connective tissue
A.
Loose connective tissue
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2.
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B.
Dense connective tissue
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C.
Dense regular connective tissue
Dense irregular connective tissue
Elastic connective tissue
Cartilage
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2.
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D.
E.
Areolar connective tissue
Adipose connective tissue
Reticular connective tissue
Hyaline Cartilage
Fibrocartilage
elastic Cartilage
Bone
Liquid connective tissue
1.
2.
Blood tissue
Lymph tissue
Mesenchyme
Description: consists of irregularly shaped
cells and delicate reticular fibers in a
semifluid ground substance
 Location: under skin in embryo
 Function: forms all other types of CT
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Mucous connective tissue
Description: widely scattered fibroblasts and
collagen fibers in jellylike ground substance
 Location: umbilical cord
 Function: support
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Adipose Tissue
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Description
 Closely packed
adipocytes
 Have nucleus
pushed to one side
by fat droplet.
 Provides reserve
food fuel
 Insulates against
heat loss
 Supports and
protects organs
Location
 Under skin
 Around kidneys
 Behind eyeballs,
within abdomen
and in breasts
Areolar
Connective
Tissue
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Description
 semifluid ground substance with:
 all three fiber types (collagen, reticular, elastic) for support
 Ground substance is made up by glycoproteins also made and screted
by the fibroblasts.
 Cells – fibroblasts, macrophages, mast cells, white blood cells
Function
 Wraps and cushions organs
 Holds and conveys tissue fluid
 Important role in inflammation and infection
Found around blood vessels, nerves and organs, lamina propria of mucous
membranes, dermis
Reticular Connective Tissue
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Description – network
of reticular fibers in
loose ground
substance
Function – form a
soft, internal skeleton
(stroma) – supports
other cell types
Location – lymphoid
organs
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Lymph nodes, bone
marrow, and spleen
reticular lamina of
basement membrane
Reticular Connective Tissue
Dense regular connective tissue
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Description: bundles of collagen with fibroblasts present in rows between
bundles
Location: tendons, ligaments and aponeuroses
Function: strong attachment between structures
Dense irregular connective tissue
Description: randomly arranged collagen fibers
and few fibroblasts
 Location: fasciae, deeper region of dermis,
periosteum, perichondrium, organ capsules,
pericardium
 Function: strength
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Elastic connective tissue
Description: Consists predominantly of elastic
fibers and fibroblasts
 Location: lung, wall of elastic arteries,
trachea, bronchial tubes, ligaments between
vertebrae
 Function: allows stretching of various organs
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cartilage
• Consists of dense network of collagen fibers and elastic
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fibers embedded in chondroitin sulfate which is
responsible for resiliency (ability to assume its original
shape after deformation)
Matrix up to 80% water.
Cells of mature cartilage is called chondrocytes occur
singly or in groups within spaces called lacunae.
Surrounded by perichondrium (blood vessels, nerves,
and source of new cartilage cells).
Cartilage has no blood supply (antiangiogenes factor)
and no nerves
Hyaline cartilage
Description: chondrocytes and collagen fibers in
bluish ground substance (resilient gel)
 Location: ends of long bones, nose, larynx,
trachea, bronchi, embryonic and fetal skeleton
 Function: smooth surface for movement of
joints, flexibility and support
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Fibrocartilage
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Description
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Function
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Matrix similar, but less firm than hyaline cartilage
Thick collagen fibers predominate
Tensile strength and ability
to absorb compressive
shock
Location
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Intervertebral discs
Pubic symphysis
Discs of knee joint
Elastic Cartilage
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Description
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Function
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Similar to hyaline cartilage
More elastic fibers in matrix
Maintains shape of structure
Allows great flexibility
Location
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Supports external ear
Epiglottis
Covering and Lining
Membranes
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Combine epithelial tissues and connective
tissues
Cover broad areas within body
Consist of epithelial sheet plus underlying
connective tissue
Three Types of Membranes
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Cutaneous membrane – skin
Mucous membrane
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Lines hollow organs that open to surface of body
An epithelial sheet underlined with layer of lamina
propria (areolar connective tissue)
Serous membrane – slippery membranes
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Simple squamous epithelium lying on areolar
connective tissue
Line closed cavities
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Pleural, peritoneal, and pericardial cavities
Covering and Lining
Membranes
Covering and Lining
Membranes
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